I am trying to find out more information about my great grandparents without much luck. Rolf Olafson born Feb 1886 in Norway, immigrated in a merchant marine ship to North Dakota at 17 years old where he became a farmer. He met and married Thora Roysland, born 1884 in Minnesota, possibly in Devils Lake area. They had 3 children, Harold, and twins Ruth and Rose. They both died in the 1960s in Montana. Any help would be great!